LeetCode: Sqrt(x)

Posted on July 29, 2018July 26, 2020 by braindenny

Implement int sqrt(int x).

Similar Problems:

Implement int sqrt(int x).

Compute and return the square root of x.

x is guaranteed to be a non-negative integer.

Example 1:

Input: 4
Output: 2

Example 2:

Input: 8
Output: 2
Explanation: The square root of 8 is 2.82842..., and since we want to return an integer, the decimal part will be truncated.

Github: code.dennyzhang.com

Credits To: leetcode.com

Leave me comments, if you have better ways to solve.

## https://code.dennyzhang.com/sqrtx
## Basic Ideas: Binary search
##              Check [1^2, 2^2, 3^2, ... n^2]
## Complexity: Time O(log(n)), Space O(1)
class Solution(object):
    def mySqrt(self, x):
        """
        :type x: int
        :rtype: int
        """
        if x == 0:
            return 0
        left, right = 1, x
        while left <= right:
            mid = left + (right-left)/2
            v = mid * mid
            if v == x:
                return mid
            elif v < x:
                left = mid + 1
            else:
                right = mid - 1
        return right

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